My process is usually to start off with an idea in my head, sitting in front of ZBrush and starting with Zspheres or, in later versions of ZBrush, DynaMesh. I rough out a sculpt to see if the idea could look good outside my head. If I find that it is worth going to the effort of finishing the sculpt, I do one of the following:
1. I continue in ZBrush and later, when the sculpt is halfway through the details, (I don't go into fine details at this stage), I decimate it using Decimation Master and export it as an OBJ to Topogun where I use it as reference mesh and start to retopologize. After I am done, the mesh gets subdivided in Topogun to level 3 or 4 (depending on the amount of detail I have) and is exported as an OBJ and imported again in ZBrush. Then I hit the Reconstruct Subdiv button three or four times, which takes me back to level 1 of the retopologized mesh.
2. I make two orthographic images of the front and side and use them as image planes in Maya to create a reasonable base mesh in terms of topology. Then I take that base mesh back to ZBrush and continue sculpting.
For this character I used the first method. I started with a sphere and converted that to a dynamesh. Using mostly the ClayBuildup, Inflate, Standard and Ryan Kittleson's Crease brushes, the character was shaped with around 1.5 million polygons. If you export that finished model with 1.5 million polygons as an OBJ to use as a reference in Topogun, your system will get really slow (mine does at least) and nothing is more counter-productive than a slow running machine. That is where Decimation Master comes in handy. I reduced the polycount from 1.5 million to around 300k using Decimation Master and exported that to Topogun where I did the retopology (Fig.04).
The typewriter parts were all created in Maya using primitive shapes and simple tools such as Extrude and Insert Edgeloops, and by moving and resizing, and scaling faces, edges and vertices. For some parts I had to create a CV Curve and used it as a path to extrude faces.
The next step was to create the UV maps. For the typewriter parts, UV mapping was done in Maya and for the character I used ZBrush's UV Master to give me something fast to start with. I also did some tweaks in Maya to make a more efficient UV map, especially in areas such as holes in the face (eyes and nostrils) or ears. Selecting UV points and using the Unfold and Relax tools repeatedly in varying degrees helped a lot (Fig.05 - 06).
For the typewriter texture, I only used Photoshop, and some images I found of grunge textures on the internet, along with some images I'd taken of an old typewriter I found in a flea market using my cell phone camera (Fig.07).